.app{
  display: flex;
  .left{
    width: 100px;
    line-height: 40px;
    height: 100%;
    text-align: center;
    background-color: #f8f8f8;
    .btn.active{
      color: #de4648;
      font-weight: bold;
      background-color: #fff;
      border-left: 2px solid #de4648;
    }
  }
  .right{
    flex:1;
    flex-wrap: wrap;
    display: flex;
    .item{
      width: 33%;
      text-align: center;
      img{
        width: 80%;
      }
    }
  }
}